Document 3eQ58Q99YVVxqyb2Dn14Kykdx

164 CHAPTER 9 1948 Guide DAIRY BARN VENTILATION3 .' A successful barn ventilating system: is one which continuously supplies the proper amount of air required by the stock, with proper distribution and without drafts, and one which removes the excessive heat; moisture) and odors, and maintains the air at a proper temperature, relative humidity, and degree of cleanliness. Barn temperatures below freezing and above 80 F affect milk produc-' tion. Milk producing stock should be kept in a bam temperature be tween 45 and 50 F. Dry stock, at reduced feeding, may be kept in a bam 5 to 10 deg higher. Calf barns are generally kept at 60 F, while hospital and maternity barns'usually have a temperature of 60 F or somewhat higher. , The heat produced by a cow of an average weight of-1000 lb may be taken as 3000 Btu per hour: .The average rate of.moisture production by a cow givirig'20;lb of-milk per day is 15 lb of water per day, or 4375 grains' per hour; To set a standard\of permissible relative humidity for cow barns is difficult. For 45 F an average relative humidity of 80 per cent is satisfactory; with'85 per cent as a limit. Where the barn volume and construction permit adequate, heating by the stabled animals, -the air supply need not be heated. The air should be supplied through or-near the ceiling. It is better to. have the exhaust openings near the. floor as larger volumes of warm air are then-held in the barn and there is better temperature control with less likelihood of sudden' change.in.bam temperature. : If a cow weighs 1000 lb and produces 3000 Btu of heat per hour, and if! a bam for the cow has 600 cu ft of air space with 130 sq ft of building exposure, one cow will require 2600 to 3550 cu ft per hour of ventilation) depending on'the temperature zone in which the barn is located. The permissible heat losses, through the. structure, based on:one. cow and depending on the temperature zone, vary between 0 043 and 0.066 Btu per (hour) (cubic foot of bam space), and 0.197-to 0.305 Btu per (hour) (square foot of barn exposure).. GARAGE VENTILATION On account of the hazards resulting from carbon monoxide and other; physiologically harmful or combustible gases or vapors in garages) the importance of. proper ventilation of these buildings cannot be. overT emphasized. During the warm months of the year, garages are usually ventilated adequately because the doors and windows are kept open. As cold weather sets in, more and more of the ventilation openings are closed and consequently on extremely cold days the carbon monoxide concentra-. tion.runs high. Many garages can be satisfactorily ventilated by natural means, par ticularly during the mild weather when doors and windows can be kept open. However,'the A.S.H.V.E. Code of Minimum, Requirements for Heating and Ventilating Garages, adopted in 1935, states that natural ventilation may be employed for the ventilation of storage sections where it is practical to maintain open windows or other openings at all times) The code specifies that such openings shall be distributed as uniformly as possible in at least two outside walls, and that the total area of such openings shall be equivalent to at least 5 per cent of the floor area. The code,further states that where it is impracticable to operate such a system of natural ventilation,.a mechanical system shall be used which shall Natural Ventilation 16S provide for either the supply of 1 cu ft of air per minute from out-of-doors for each square foot of floor area, Or for removing the same amount and discharging it to the outside as a means of flushing the garage4. ReRseesaercahrch on garage ventilation, undertaken by the A.S.H;V;E-. Com mittee on Research at Washington University, St. Louis, Mo., and atthe University of Kansas, Lawrence, Kans., in cooperation^ with the A.S.H.V.E. Research Laboratory, and at the A.S.H.V.E. Research Laboratory, has resulted in authoritative papers on. the subject. : Some of the conclusions from work at the Laboratory are listed in the following statements': 1. Upward ventilation results in a lower concentration of carbon monoxide at ,the ' breathing line and a lower temperature above the breathing line than does downward ventilation, for the same rate of carbon monoxide production, air change and the same' t-e-m2p. eAraltouwreerartathteeo3f0a-iinr.clheavnegl.e and a smaller heating load are required with upward tha3n. wIniththdeoawvnewraagredcvaesentuilpawtioanrd. ventilation results in a lower concentration of ca.rbon monoxide' in the occupied portion of a garage than that obtained with mixing of the exhaust gases and the air supplied. `However, the variations in concentration from point to point, together with the possible failure of the advantages of upward ventilation to accrue, suggest the basing of garage ventilation on complete mixing and an air change sufficient to dilute the exhaust gases to the allowable concentration of carbon monoxide. " 4: The rate of carbon monoxide production by an idling car is shown to vary from 25 to 60 cu ft per hour, with an average rate of 35 cu ft per hour. i '1' : 5. An air change of 350,000 cu ft per hour per idling car is required to keep the carbon monoxide concentration down to one part in 10,000 parts of air. REFERENCES I '--Predetermining Airation of Industrial Buildings, by W. C. Randall and E. W. Conover (A.SJLV.E;' TransNacetuitoranlsZ, oVnoeLin37V, e1n93ti1la. tpio. n6,0b5y). J. . E. Emswiler (A.S.-H.V.E. Tr.ansactions, Vol. 32. 1926, p. 59).: )' *--Dairy Barn Ventilation, by F. L. Fairbanks (A.S.H.V.E. Transactions. Vol. 34, 1928, p. 181); Cow Barn Ventilation, by Alfred J. Offner (A.S.H.V.E. Transactions,'Vol. 39. 1933,-p. 149). For additional information on this subject refer to Technical Bulletin, U. S. Department of Agriculture (1930), by Mi A. R. Kelley. - Also see Air Conditioning of Farm Buildings, by F. L. Fairbanks (Agricultural Engineering, Nove--mCboedre. To9f3M7,inpi.m4u8m5).Requirements for Heating and Ven..tilating...G. arages (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 30). .................... Airation Study of Garages by W. C. Randall and L. W. Leonhard (A.S.H.V.E. Transactions, Vol. 36, 193A0,.Sp.H2.3V3.)E. . Research Rspoxti No. 874--Carbon Monoxide Concentration in'Garages, by A. S. Langs* dorf and R. R. Tucker (A.S.H.V.E. Transactions, Vol. 36,1930, p. 511). A.S.H.V.E. Research Report No. 935--Carbon Monoxide Distribution in Relation to the Ventilation of an Underground Ramp Garage, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, VolA. 3.S8.H1.9V3.2E. .pR. 4e3s9e)a.rch Report No. 934--Carbon Monoxide Distribution in Relation to the Ventilation of a One-Floor Garage, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, Vol. 38,1932, p. 4A24.S)..H.V.E. Research Report No. 967--Carbon Monoxide Distribution in Relation to the Heating and Ventilation of a One-Floor Garage, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Trans* actCioanrsb,oVnoMl. o3n9o, x1i9d3e3,Spu.rv3e9y5s). of Two Garages, by A. H. Sluss, E. K. Campbell and Louis M. Farber -- ------------------An 1Q5L1 tv 2fl3V